rushmer



March 24, 1964 R. H. RUSHMER BONDED ABRASIVE ARTICLE Filed Dec. 27, 1960 INVENTOR. RALPH H. RUSHMER ATTORNEY United States Patent 3,126,262 BONDED ABRASIVE ARTICLE Ralph H. Rushmer, Lewiston, N.Y., assignor to The Carborundum Company, Niagara Falls, N.Y., a corporation of Delaware Filed Dec. 27, 1960, Ser. No. 78,666 4 Claims. (Cl. 51298) This invention relates to bonded abrasive articles and more particularly to bonded abrasive wheels containing a novel chlorine-containing additive for improved cutting action and better storage characteristics.

It has been known heretofore that the addition of chlorine-containing fillers to bonded abrasive wheels such as hot pressed billet wheels provides a desirable cutting action. One material which has been utilized for this purpose is sodium chloride or common table salt. However, sodium chloride surfers from the disadvantage that it is hygroscopic and the results of this characteristic are believed to be obvious. Thus, during storage, wheels containing this material pick up moisture from the humidity content of the air and become slimy, difficult to handle and generally unaesthetic from a customers point of view. Accordingly, manufacturers of bonded abrasive articles have been faced with the challenge of providing bonded grinding wheels of high cutting efiiciency, yet which remain dry in storage.

It is accordingly an important object of the present invention to provide improved bonded abrasive articles such as grinding wheels.

Another object of the invention is to provide a novel chlorine-containing additive which imparts improved cutting action to bonded abrasive wheels and yet is not bygroscopic, thus providing bonded abrasive articles of improved storage characteristics and greater customer appeal.

Another object is to provide improved bonded abrasive articles containing a chlorinated, high-melting organic chemical compound as an additive.

Further objects of the invention will become apparent from the accompanying specification and drawings wherein,

FIGURE 1 is a side elevation view of one form of grinding wheel embodying the present invention.

In accordance with the present invention, bonded abrasive articles containing an abrasive such as silicon carbide, are provided with improved abrading and cutting characteristics by incorporating therein during the process of their manufacture, selected amounts of a novel chlorine-containing additive. The additive of this invention is perchloropentacyclo (521.0 .0 .6 decane. This compound may be formed by isomerizing a product of the empirical formula C Cl produced from his (pentachlorocyclopentadienyl), C Cl The process by which it is produced is disclosed in U.S. Patent No. 2,849,- 499, granted August 26, 1958, to McBee et al. In New Products From Hooker Research, Bulletin No. 15- A, published February 1960 by Hooker Chemical Corporation, Niagara Falls, New York, on page 6, the struc 'tural formula are given.

.The novel additive is a very high melting organic chemical compound and consequently is stable at high temperatures. For example at temperature as high as 300- 350 F., this material is very stable in supplying chlorine atoms to the grinding face. It has a melting point of 485 C. (sealed tube), sublimes above 240 C., and has a specific gravity of 2.020.

While the invention may be used in various forms of grinding wheels, the drawing illustrates one form of wheel embodying the invention. As shown thereon, reference numeral 10 designates generally a grinding wheel which is of disc-like configuration having a circular periphery 11. The wheel is of uniform thickness and is provided at the center with a concentric arbor hole 12 that provides a means for mounting the wheel on a rotatable shaft, not shown. The wheel structure is comprised of abrasive particles 13 that are held together by a bonding material 14. The bonding material contains as an ingredient thereof the additive of the present invention described above.

In preparing improved bonded abrasive articles in accordance with the present invention, the perchloropentacyclo-(5.2.1.'0 .O .O decane is added to a forming mixture to be used for the production of such articles in an amount in the range from 0.5 weight percent to about 20 weight percent of the mixture. Preferred amounts of the present additive will be in the range from about 1 weight percent to about 5 weight percent of the mixture. The optimum additions of the additive of the present invention in any particular case will depend upon conditions of use such as the nature of the work being ground or cut, the amount of stock to be removed and whether grinding or cutting is to be carried out wet or dry, among other factors.

In the practice of the invention, the additive has been employed in particulate form to facilitate its admixture with other ingredients which go into the composition of a bonded abrasive wheel. The particle size employed can vary although it has been found that particle sizes in the range of 30 mesh and finer are suitable.

The inclusion of perchloropentacyclo-(5.2.l0 0 20 decane into the bond composition provides a high degree of abrasive efiiciency and also overcomes the disagreeable hygroscopic properties of sodium chloride. Further, the additive has little if any effect upon wheel life, and in some instances wheel life is increased. The additive can be substituted for a portion of the filler employed in producing bonded abrasive articles, or can be added in addition to the filler. One typical filler with which the present additive can be used is cryolite.

The additive is compatible with most bonds employed for the production of bonded abrasive articles, being particularly adapt-ed for use with organic bonds. As utilized in this disclosure, the term organic bond encompasses the synthetic and natural resins including the phenol formaldehydes, urea formaldehydes, melamineformaldehydes, epoxies, alkyds, polyesters, modified phenolics, natural and synthetic rubbers, shellac and the like:

The present invention is adapted to the production of bonded abrasive articles wherein the abrasives include silicon carbide, aluminum oxide, bauxite, zirconia, flint, garnet, Alundum, and the like, either singly or in admixture.

The following examples illustrate the principles of the invention; the manner in which bonded abrasive wheels are made, and the results of grinding tests employing wheels made by the present invention.

Example I Briquettes were made from a grinding wheel mix to illustrate the compatibility of the additive perchloropentacyc1o-(5.2.1.0 .0 .0 decane, with a resinoid bond.

The ingredients of the composition of the batch were as follows:

Percent by weight 5 Mix A Control Aluminum oxide grain, 12-16 grit 69. 3 69. Phenolic resin 4 Inorganic mineral fillers 1 NaC 5 Perehloropentacyelo-(5.2.1.0 .0

The ingredients were admixed and molded under pressure of 3500 p.s.i. and a temperature of about 330 F. for about twenty minutes to form A.S.T.M. tensile briquettes. Thereafter the molded briquettes were cured at a temperature of 350 F. for a period of about eight These results illustrate that a grinding wheel composition containing the perchloropentacyclo-(5.2.1.0 .0 .0 decane had tensile properties commensurate with those of a similar composition containing sodium chloride, illustrating the good compatibility of the additive with the bond.

The composition containing the additive was not hygroscopic as compared to the control, and thus provides a distinct advantage over the composition containing sodium chloride, as regards improved storage characteristics.

Example II Hot pressed bonded abrasive wheels were made for grinding tests employing perchloropentacyclo-(5.2.l0 0 0 decane as additive and comparison was provided by sodium chloride additive. The ingredients and the composition of the batch were as follows:

Percent by Weight Wheel 13 Control Aluminum oxide grain, 12-16 grit 75.0 Phenolic resin 9.0 Inorganic mineral fillers.-. 14. 5 Na 01 1. 5 Perchloropentacycle-(5.210 0 {0 deeane 1. 5

The ingredients were admixed and molded into 16" x 2 /2" x 6" wheels under a pressure of about 3500 p.s.i. and a temperature of 330 F. for 50 minutes. Thereafter the wheels were cured at 350 F. for about 8 hours.

Grinding tests were run on the wheels with the following results:

Wheel B Control Pounds metal removed 36. 60 35. 86 Pounds wheel loss 2. 474 2. 36 Performance factor (M /W) 541. 5 544.8

1 M=pounds metal removed; W=pounds wheel loss.

The results indicate that wheels made in accordance with the present invention have grinding efiiciencies commensurate with wheels containing an equal amount of sodium chloride as the chlorine-containing additive. However, it is to be noted that wheels made in accordance with the invention are not hygroscopic as are wheels containing sodium chloride.

Example III Hot pressed bonded abrasive wheels were made for grinding and bursting strength tests employing perchloropentacyclo-(5.2.1.0 .0 .0 decane as additive The ingredients and the composition of the batch were as follows:

Percent by weight, wheel C Aluminum oxide grain, 12-16 grit 74.0 Phenolic resin 11.0 Perchloropentacyclo-(5.2.l.0 0 0 decane 1.2 Inorganic mineral fillers 13.8

The ingredients were admixed and molded into 16" 1: 2 /2 x 6" wheels under a pressure of about 3500 p.s.i. and a temperature of 330 F. for 50 minutes. Thereafter they were cured at 350 F. for about 8 hours.

Grinding tests were run on the wheels with the following results:

Wheel C Pounds metal removed 39.68 Pounds wheel loss 2.678 Efiiciency ratio 14.8

Bursting strength tests provided the following results:

Bursting speed (surface feet per minute) New wheel 28,400 Stub (after abuse of grinding) 30,300

While no control wheel is available for comparison in the present example, the above results indicate that a high quality wheel of fast-cutting action was produced. Further the wheels displayed a high strength and the breaking speeds were good; the stub bursting speed being very good. These are superior to bursting speeds in the range of 24,00028,000 s.f.p.m. which are typical for this type of wheel. Further, the wheels were not hygroscopic as compared to wheels containing sodium chloride.

Example IV Hot pressed bonded abrasive snagging Wheels were made in a production operation employing the batch formula and conditions of Example III. These wheels were made in a size of 24" x 3" x 12". Grinding laboratory tests were run on the wheels with the following results:

Typical Produc- Prior tion Art Wheel snagging heel Pounds metal removed 35. 33 26. 29 Pounds wheel loss 2. 754 1. 350 Performance factor (M /W) 453. 23 373. 5

l M=pounds metal removed; W=pounds wheel loss.

These results prove that perchloropentacyclo-(5.2.1.0 .0 .0 decane can be utilized in production to provide bonded abrasive wheels having high quality, improved cutting action, and non-hygroscopic properties.

Example V Cold pressed billet wheels containing perchloropentacyclo-(5.2.1.0 .0 .0 decane Percent by Weight were made. The ingredients and the composition of the 5 batch were as follows: Wheel F Control emembyweeht r tfifitisii fi iiltziiff fi: t2 t2- Cryolite 14.5 16 WheelD Control 10 Perchloropentacycle-(5.2.1.0 IROHOM) decane-.. 1.5

lgl umi nnn oxide grain, 12-16 grit he ingre ielts gerle agi rlixeg and r I/1oldeddur111der pres; em resin sure into cut-o w ees 1 x 32 x 8 an t en cure t .2.1. H 1.5 i iiiiiffil.Tii fifinfnfnpulf fi i fiun 1 129 at 360 F. for 9 hours. Tests were run with a water- Caom 15 base coolant, cutting cold-rolled steel bar stock. Test results are as follows: The ingredients were admixed and cold pressed into 16" x 2 /2 x 6 wheels at 5000 p.s.i., and then cured Wheel}; Control at 350 F. for 6 hours. Grinding tests were run on the wheels with the follow- 20 Ratio; Area cut/ma Wheel 1055 162 612 mg results:

The results show improved performance over wheels WheelD Control without the novel additive.

Pounds metal removed 42.23 36.82 Example VH1 Yg g l$g?fig ;;w 1 j 2% 5593 Cut-01f wheels of a size of 16" x Ma x 1" were made Bursting s eed (stub, used wheel), s.t. .m 19,800 21,400 wherein perchloropentacyclo (5.2.1. 0 .0 .0 decane replaced part of the cryolite filler. These wheels were 1M=p0undsmeta1 removed; w=poundswheelloss. laboratory tested for dry cutting bar stock. The in- The foregoing results indicate a high rate of metal gredients and the composition of the batch W as removal and high performance factor. Bursting speeds follows! were very good. The test results showed an increase in the rate of metal removal. The overall performance Percent by Weight as measured in the testing laboratory was superior to the performance of the wheels which did not contain the WheelG Control perchloropentacyclo-(5.2.1.0 .0 .0 decane.

Aluminum oxide grain, 30 grit. 68. 3 68.0 Example VI ghenlolie resin 0 1g6? 1 O] P f I '3 Bonded abrasive cut-otf wheels were made employ- Pihend Cement .ei ing hl l (5 2 1 .02,6 ()3,9 05,8) decane as 40 Perchloropentacyclo-(521.0 .0 .0 decane--- 1.4 the chlorine-containing additive replacing part of the cryolite filler normally used. The ingredients of the com- The Ingredients Were COmblIled a d m ld d mt Wheels o ition of the b t h w r as f ll at 3750 p.s.i., and were then cured at 360 F. for hours.

The wheels had a density of 43 grams per cubic lnch. Percentby Weight Cutting tests provided the following results:

WheelE Control WheelG Control A1 d 72.0 72,0 Diameter loss inches 0.191 0.199 16. 0 15. 0 Cuts p square inc 7. 6. 4 cr olite 10 0 11. 5 Rctest diameter loss, 1]1 0heS 0. 179 0.199 Perehloropentacyelo-(5.2.1.O -.0 .0 decane 1. 5 etest, Cu s P61 sq are 111011 19. 2 17.1

The ingredients were admixed and molded under a T results ShOW that eificiency increases up to 12% pressure of about 3750 p.s.i. into cut-off wheels 16" x are p q y t novel addltlve In accordance wi h Ma" x l" which were cured at 360 F. for 9 hours. Wheel th prese t lnventl n. density was 42.8 grams per cubic inch. Example IX Cut-01f tests were run on the wheels by making 80 dry cuts through C1020 bar Stock of 2 diameter at one Reinforced reslnold cut-off wheels of greater thickness second per cut. The following results were provided. than those of P examples were Preparec emPloylng perchloropentacyclo-(5.2.l. 0 .0 .'0 decane 1n the [Wheel E Control system. The ingredients of the batch were as fol- Diameter loss, average of 3 wheels, lnehes 0. 264 0. 282 Outs per square inch of abrasive 13. 6 11. 2 Percent by Weight The foregoing results indicate that perchloropenta- WheelH Wheel J Control cycle-(5.2.1.0 .0 .0 decane provides improved efli- A1 m rue. 'de Grain 24 rt 67.7 67.7 67.7 ciency in dry cutting of steel bar stock as compared to a gflg inf-L 262 26.2 26-2 wheel using straight cryolite as a filler. Also it provides cryolite 2.5 3. 5 a non-hygroscopic product. Pe r e go r o enteeye1o-(a2.rumma e,t 1 0 3 O a0-.. IIIIIIII1:111:11: 2:6 2:6 "52:6

Example VII Resinoid cut-off wheels were prepared wherein part of The ingredients were admixed and molded into cut-ofi? the cryolite filler was replaced by perchloropentacyclowheels 16" X /1 X 1" at a pressure of 750 p.s.i. and

6 (5.2.1.0 .O .0 decane. The' ihgredients and the composition of the batch were as follows:

WheelHl Wheel .T Control Diameter loss, inches 0. 913 1.108 0. 909 Time per cut, seconds 9 8 8 Number of cuts per square inch 0! abrasive 0. 45 0.37 O. 45 Bursting speed, s.f.p.m. 34, 900 35,100

The test results show that the overall performance of the wheels was equal to the performance of wheels which did not contain perchloropentacyclo-(5.2.1.0 .0 .0 decane bonded abrasive article containing the following ingredi ents by weight:

Percent Abrasive grain 65-75 Phenolic resin 9-27 Cryolite filler 10-21 Perchloropentacyclo (521.0 .0 .0 decane (010C112), granular 1-3 2. A raw batch mixture as defined in claim 1 in which the perchloropentacyclo 521.0 .0 .0 decane (C Cl is present in an amount equal to from about 1 to 1.5% by weight.

3. A non-hygroscopic bonded abrasive article consisting essentially of abrasive grain and a bond for said grain, said bond comprising about 25-35% by weight of said article and consisting essentially of 9-27% phenolic resin, 10-21% cryolite filler, and 13% granular perchloropentacyclo-(5.2.1.0 .0 .0 decane (C Cl the percentages of said bond ingredients being percentages by weight based upon said article.

4. A bonded abrasive article as defined in claim 3 in which said perchloropentacyclo-(5.2.1.0 .0 .0 decane comprises from 1 to 1.5% by weight of said article and is uniformly distributed throughout said bond.

References Cited in the file of this patent UNITED STATES PATENTS 1,900,430 Daniels Mar. 7, 1933 2,111,248 Novotny Mar. 15, 1938 2,125,893 Daniels Aug. 9, 1938 

3. A NON-HYGROSCOPIC BONDED ABRASIVE ARTICLE CONSISTING ESSENTIALLY OF ABRASIVE GRAIN AND A BOND FOR SAID GRAIN, SAID BOND COMPRISING ABOUT 25-35% BY WEIGHT OF SAID ARTICLE AND CONSISTING ESSENTIALLY OF 9-27% PHENOLIC RESIN, 10-21% CRYOLITE FILLER, AND 1-3% GRANULAR PERCHLOROPENTACYCLO-(5.I.1.0**2.6.0**39.0**5.8) DECANE (C10CL12), THE PERCENTAGES OF SAID BOND INGREDIENTS BEING PERCENTAGE BY WEIGHT BASED UPON SAID ARTICLE. 